1. Field of the Invention
The present invention relates generally to converting animal wastes to useful products, and more particularly, but not by way of limitation, to a process for simultaneously converting swine, poultry and cattle wastes to methane-containing gases and an animal feed product.
2. Description of the Prior Art
Various processes for converting animal wastes into more valuable and useful products have been developed heretofore. For example, U.S. Pat. No. 3,838,199 discloses a process wherein cattle manure is combined with water to form a slurry and the slurry subjected to thermophilic anaerobic fermentation to produce a methane gas product and an animal feed product. U.S. Pat. No. 3,973,043 discloses a similar process for converting feedlot fecal waste materials into methane and animal feed. U.S. Pat. No. 3,878,303 discloses a method for the treatment of animal wastes wherein an aqueous medium containing the animal wastes is prepared and a foam stabilizer such as a surface active agent or a protective colloid is added to the resulting aqueous medium. The aqueous medium is then foamed and the foam charged to a fermentation vessel to permit bacterial decomposition of the animal wastes.
By the present invention an improved process for simultaneously converting swine, poultry and cattle wastes to methane-rich gases and a feed product is provided which is efficient and economical to carry out.